How do you calculate feeder load

Teague Allen

Member
Location
New Mexico
Occupation
Electrician
I got asked this question and even after going into the NEC I was unable to figure out how they got the number they did please help.

A 1,600 sq ft dwelling unit contains 74 receptacle outlets including 14 receptacles in the kitchen, laundry, and dining areas. Using the standard calculation what is the computed feeder load for lighting receptacle, small appliance, and laundry loads in volt amps for this dwelling?

Answer: Table 220.12, 220.52(A), 220.52(B) 9,300 - 3,000 =66,300 VA 6,300x0.35 = 22,205 VA 3,000 + 2,205 = 55,205 VA. This made no since to me at all and again after going into the NEC those were not even close to the numbers I got. Please let me know how I would go about figuring this out the right way.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Answer: Table 220.12, 220.52(A), 220.52(B) 9,300 - 3,000 =66,300 VA 6,300x0.35 = 22,205 VA 3,000 + 2,205 = 55,205 VA. This made no since to me at all and again after going into the NEC those were not even close to the numbers I got. Please let me know how I would go about figuring this out the right way.


They obviously made a mistake... 9,300-3000 = 6,300 not 66,300

6,300 *.35 = 2205

2,205 + 3000 = 5205va #3
 

Teague Allen

Member
Location
New Mexico
Occupation
Electrician
Ok cool, I kinda thought so but since I didn't know I wasn't sure if there was something I had to multiply by.
My last question is why is it multiplied by .35? I don't understand where the 9300 came from I know you need 3VA per sq ft for general lighting and that you need 1500VA for appliances. The 9300 I don't get through. Thank you for all the help I'm still pretty new to all this just want to study while I'm doing my aprenticeship
 
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